“For God, who said, ‘Let light shine out of darkness,’ has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ.” (2 Corinthians 4.6)
To start understanding this verse we must first see the analogy Paul is making here with Genesis 1.1-3:
In the beginning, God created the heavens and the earth. The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. And God said, ‘Let there be light,’ and there was light.
He we see that darkness is covering the earth and God, through the word that is Christ (cf. John 1.1-3), speaks light forth out of the darkness. In the same way we are presented the blinded darkness which is unbelief and God who speaks light into hearts which is salvation.
This is seen in various ways elsewhere in the New Testament. Ephesians 2.4-5 tells us that God takes those who are dead in their trespasses and sins and “[makes them] alive together with Christ.” 1 Peter 1.3 says that “[a]ccording to his great mercy, [God] has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead.” Titus 3.4-7 lets us know that because of God’s “goodness and loving kindness . . . he saved us . . . by the washing of regeneration and renewal of the Holy Spirit, whom he poured out on us richly through Jesus Christ our Savior.”
All of this points to two things. One, it is God who both initiates and completes our salvation. He takes us from darkness and into light, from death and gives us life. Nowhere is any conditional offer mentioned. Nowhere is God asking if we want this and then letting us decide. God sovereignly works, and when he works he does it all the way.
Second, we see in this truth the statement of Acts 4.12 exemplified:
And there is salvation in no one else [but Jesus], for there is no other name under heaven given among men by which we must be saved.
Not only does God provide salvation, but the only means by which salvation is made known is “in the face of Jesus Christ.”